[Self-Hosted] Add Rate Limiting with Flask-Limiter

[glenn-sorrentino]

• Model the work in main and personal-server
• Implement Flask-Limiter
• Use Redis
• Create page for fail state

[glenn-sorrentino]

@ritik2311 @iAnonymous3000 Either of you wanna take this? This is for the core v1 self-hosted version.